This invention relates in general to cable gripping devices and, more specifically, to an adjustable safety device for connecting a personal safety lanyard to a cable.
A wide variety of devices have been developed which permit a cable, rope or rod-like member to be gripped at a selected point along its length to position a structure attached to the gripping device to be positively positioned at the selected location. While many of these are acceptable for their intended uses, they do not possess the degree of safety, reliability and "fail-safe" characteristics when used in a personal safety system protecting workers in high, exposed locations, workers in extra-vehicular excursions in outer space, etc.
One type of known gripper uses a plurality of wires coiled around the cable to be gripped in an interlaced mesh-like tube, where the tube contracts radially into a gripping relationship with a cable lying along the tube axis when the ends of the mesh tube are moved apart. Typical of such arrangements are those shown by Clay in U.S. Pat. No. 3,343,231 and by DiPalma in U.S. Pat. No. 2,698,150. While these provide a secure grip when actuated, they all have two latched positions; engaged and disengaged. Thus, it is possible to inadvertently disengage, or not properly engage, the gripping device, which would permit the device to slip along the cable possibly resulting in a fall and injury to a worker relying on the device.
In some cases, external springs have been used to increase the force moving the ends of the mesh tube apart to increase the gripping force. While this insures the gripping strength, it does not prevent accidents when the spring is disengaged.
Thus, there is a continuing need for improved cable gripping devices.